Process of making organic intermediates



A No Drawing.

riser WORKS, INC., OF .YQBK, N. Y., A CORPORATION OF VIRGINIA irnoonss-ornnxme oRGAivIo INTERMEDIATES} This invention relatesto theproduction of organic intermediates and particularly to processes ofsubstituting the halogen 1n halogen-nitrobenzenes with an alkoxy groupto form alkoxy nitrobenzenes, and has as a general object the productionof such compounds in a convenient, efiicient andeconomical manner. 7

A more specific object of the invention to provide a process ofpreparing alkoxynitrobenzene' from halogemnitrobenzenes 1n approximatelyquantitative yields, at. nor; mal pressure and at relatively lowtemperatures.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps and the relationand order of one or more of such steps with respect to each of theothers thereof, which will be exemplified in the process hereinafterdlsclosed, and the scope of the application of which will be indicatedin the claims.

alkoxy-nitrobenzenes have therefore either.

Experimental attempts have'been made to prepare these compounds byheating the halogen-nitrobenzenes with metallic alcoholates but, due tothe steps employed, various side reactions occurred resulting in thefor-.

mation of aZo and azoxy compounds and the yields of alkoxy-nitrobenzeneswas consequently small.

Commercial methods of preparing the utilized materials of an entirelydifferent type or have resorted to the use of caustic alkalies and waterto decrease the violence and rapidity of the reaction, in an endeavor hto minimize the loss due to the side reactions. Heating under pressurewas fre quently used in such processes, the materials were generally allpresent at the beginning and the yields were unsatisfactory foreconomical commercial operation.

I have discovered that the aforesaid side reactions may be substantiallyentirely avoided, and approximately theoretical yields ofalkoxy-nitrobenzenes may be obtained from the halogen-nitrobenzene used,if the metallicalcoholate, prepared by dissolving an alkali Applicationfiled. August 13,1926, se i rn'o.129,089)

metal in dry alcohol, is slowly addedtothe heated halogen-nitrobenzene.By such procedure I have found that although thetemper ature andpressure may be varied within quite wide limits, neverthelessit is bothconvenient and practical to carry out the reaction at rela tively lowtemperatures, as, for example, at

about the boiling pointof the alcohol used.

As alresult of the possibility of using such temperatures, it is notnecessary that the halo gen-nitrobenzene be diluted with'alcohol, asheretofore, although, due to the tendency to thicken during thereaction, such dilution is generally desirable. Also I have found thatother substances may be used as a diluent;="although the use of alcoholis preferred since it can then subsequently be distilled off from themass and used directly again Without pus rification.

The following example is illustrativegof tised:

In the preparation of ortho-nitroanisole, 157.5 parts by weight-0fortho-nitrochloro benzene is mixed with an equal weight" of methylalcohol and heatedtoabo'ut- C. under a reflux. A solution of' 23 partsby" Weight of metallic sodium dissolved in about the manner in which myprocess may be'prac- ERIK CLEMMENSEN, or NEWARK, NEW YORK, AssIeNon 'rorm'rninson Ankara 200 parts of methyl alcohol is added slowly at a ratesuch that there is at no time present a substantial excess of thealcoholate. The

temperatureis maintained at about 70 0.,

the time of addition being about/l8 hours. Thereafter the methyl alcoholis distilledoff and enough water is added to the remainder to dissolvethe formeds'odium chloride. At this time the ortho-nitroanisoleseparates as a layer 'on top of the sodium chloridesolution and may beseparated in the usual way. The l yield is substantially quantitative..7

Although the above example is illustrative only of the process ofpreparingortho-nitroa-nisole, yet it is to be understood that myinvention is applicable to the preparationof other compounds of asimilar nature, such as, para-nitroanisole, di-nitroanisole etc and thatother halogen-nitrobenzenes such as para-nitrochloro benz'enes,di-nitrochlorobenzene etc., and other alcoholateslsuch as ethylalcoholate etc, and other alkali metals may be used if desired; also aspointed out above,

other temperatures may be used; a particular any given instant.

Since certain changes may be made in carrying out the above processwithout departing from the scope of the invention, it is intended thatall matter contained in the above" description shall be interpreted asillustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic andspecific features of they invention hereindescribed, and all statements of the scopeofthe invention which, as a.matter of language, might. be said to fall the-rebetween.

.Having described my invention, what I claim asnew and desireto secureby Letters Patent is: I a 1 v 1. A process of making analkoxy-nitrobenzene which includes slowly adding a metallicalcoholate'to a halogen-nitrobenzene while maintaining the mixture atsubstantially atmospheric pressure and at an elevated temperature.

2. Aprocess of making an alkoxy-nitrobenzene which includes slowlyadding a me tallic alcoholate to a halogen-nitrobenzene in the presenceof a solvent of the latter com pound while maintaining the mixture atsubstantially atmospheric pressure and at an elevated temperature.

3. A process of making an alkoxy-nitrobenzene which comprises slowlyadding an alcoholic solution of a metallic alcoholate to ahalogen-nitrobenzene while holding the mixtureat a temperatureofapproximately the boiling point of the alcohol and at sub stantiallyatmospheric pressure.

4:. A process of making an alkoxy-nitrobenzene which comprises slowlyadding an alcoholic solution of a metallic alcoholate to ahalogen-nitrobenzene at a rate such that there is at no time present asubstantial uncombined quantity of unreacted alcoholate, while holdingthe mixture at a temperature of approximately the boiling point of thealcohol and at substantially atmospheric pressure. r

5. Aprocess of making a nitroanisole which includes slowly. adding asolution formed by dissolving analkali metal in methyl alcohol to ahalogen nitrobenzene while maintaining the mixture at substantiallyatmospheric pressure and at an elevated temperature.

6. A process of making a nitroaniso le which includes slowly adding asolution formed by dissolving an alkali metal in methyl alcohol, to ahalogen-nitrobenzene,

' while holding the mixture at about C.

7. A process of making a nitroanisole which comprises slowly adding asolution cohol.

about 70 C.' under a reflux, and, while maintaining the temperaturesubstantially constant, slowly adding a solution formed by'dissolving'an alkali metal in methyl al- 9. A process which, comprisesdiluting 157 .5 parts by weight of ortho-nitrocholorobenzene withapproximately an equal amount of methyl alcohol, heating-the mixture toabout 70 C.

under a reflux, and, while maintaining the temperature substantiallyconstant, adding to; the mixture a solution formed by dissolving 23parts by weight of metallic sodium in about200 parts of methyl alcohol,theaddi tion being made at a rate such that *there is of makingortho-nitroanisole at no timepresent a substantial quantity of Iunreacted alcoholate. e g

In testimonywhereof I aflix my signature.

7 ERIK CLEMMENSEN.

